1. Field of the Invention
This invention relates generally to synthetic jets and, more specifically, synthetic jets that interact with working fluids at temperatures outside an optimum working temperature range of the synthetic jets.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Synthetic jets are known for use in pulsing jets of fluid into a flow of working fluid such as hot jet engine exhaust gases. One type of synthetic jet used for this purpose is a dual bimorph synthetic jet (DBSJ), which comprises a working fluid chamber defined by two dual bimorph piezoelectric plates spaced apart by a flexible spacer ring hinge. A working fluid port provides fluid flow communication between the working fluid chamber and a flow of working fluid. The plates include respective bimorph piezoelectric structures arranged to alternately expand convexly away from one another and concavely toward one another in response to applications of voltage of alternating polarity. Convex expansion of the bimorph piezoelectric structures away from one another increases the volume of the working fluid chamber and draws working fluid into the working fluid chamber. Concave expansion of the structures toward one another decreases the volume of the working fluid chamber and expels working fluid from the working fluid chamber through the working fluid port. However, the piezoceramics in DBSJs generally limit the use of DBSJs to relatively low temperature environments.
Distributed synthetic jet actuators are known to have been used in a thermal management system for a heat-producing body. The synthetic jet actuators are arranged to remove heat energy from a heat-producing body by moving coolant working fluid past the body in close proximity.
Synthetic jets are also known to have been arranged in a series or “stack” comprising a plurality of bimorph plates arranged in a parallel spaced-apart fashion to define intervening synthetic jet working fluid chambers that are in fluid communication with a flow of working fluid. In this type of arrangement the bimorph plates are actuated in an alternating fashion to produce alternating pulses of working fluid. In other words, working fluid is being expelled from every other chamber while fluid is being drawn into all the intervening chambers, and vice versa.